In recent years, radio communication equipment typified by portable telephone terminals have been increasingly modified into multiband systems, so that a plurality of pieces of radio equipment are incorporated in one telephone equipment. Demands for smaller-size and thinner portable telephone equipment, however, have been posed continuously, leading to strong demands for the downsizing and thinning of components incorporated therein. Demands for reducing costs of radio communication equipment also are strong, and in many cases, the downsizing and mounting cost reduction are achieved by combining some of incorporated components into one module.
Among the incorporated components of radio communication equipment, acoustic wave filters and duplexers using the same have difficulties in being integrated in other semiconductor components. Therefore, they have been mounted separately from semiconductor components. Recently, the number of filters and duplexers incorporated in one portable telephone terminal has increased rapidly owing to its multiband configuration, and therefore, demands for combining the filters and duplexers into modules, respectively, have increased. Further, there are also demands for the further downsizing and thinning of such modules.
Against such a backdrop, a module in which a plurality of acoustic wave filters and duplexers using the same are installed has been developed actively.
Here, in order to develop a small-size module, it is preferable to arrange individual filters and duplexers as closely to one another as possible when mounting them on a module substrate. Besides, it is preferable to arrange electric lines in the module substrate closely to one another. Still further, since acoustic wave filters and duplexers themselves are preferably downsized as a matter of course, it is also preferable to closely arrange electric lines in a package for housing acoustic wave filter elements. Still further, JP 2008-271421 A discloses an acoustic wave filter in which a filter element is mounted on a multilayer substrate for the downsizing.
When electric lines in an acoustic wave filter are arranged closely, unnecessary electromagnetic coupling tends to occur between the electric lines. Further, when electric lines in a module substrate are arranged closely, unnecessary electromagnetic coupling tends to occur between the electric lines. When unnecessary electromagnetic coupling occurs between electric lines, the suppression by the filter or the isolation by the duplexer tends to degrade easily.